New Divemaster air consumption

[Nosmosis]

I started diving less than a year ago, but I immediately fell in love with it and went all in. I’ve started my divemaster course and intend to do the IDC after 6 months as a divemaster. I’m confident and comfortable with my skills, except air consumption. I’m 6’2” 240 lbs so I suck a lot of air. 20-30 ft I average an hour but at 50 ft it’s more like 35-40 mins (with 3 min SS and coming up with 5-6 bar). Will I encounter problems as a DM? Ive never been the diver that required the group to turn around because of low air, but worried I’ll lead a dive and have to turn before a paying customer needs to. Is there anything I can do to decrease my air consumption?

I’m about your size…240 lbs 6’3”. I used to be a gas hog. Couple things I started doing…
1. Getting the fundamentals better…buoyancy, trim, propulsion, breathing…how? I did some coaching with some people that were tech divers/tech instructors who were good in the water. They filmed me. Gave me good, detailed feedback. We watched video. We got my gear streamlined, neat and tidy. I dive alot…probably 100+ dives before I saw some really strong improvements where people started complimenting me in the water. Still an ever developing work in progress though…Some good reading i found in Mark Powell’s book on Technical diving which talks about breathing in a detailed way. GUE Fundamentals was really game changing. Coaching was too - namely with James Blackman— who got me very data oriented in tracking my breathing, calculating SAC rates and logging them. I now have detailed records that help me see what my SAC, SAC, RMV are in quarries, Great lakes, Florida, Cave Country, New Jersey and the gear I had and conditions so I know what my performance was, is likely to be and what’s going to influence it.

2. Weight. Can over emphasize how much getting weighted right has helped. I try to dive as close to a balanced rig as possible but getting the gear and weight right is at least in the data i have in my dives so so so important and directly correlated with the gas consumption. It took lots of diving in different configurations and environments to get it right beyond the theory. Sometimes I’m getting SAC rates of a 95 lb girl (not all the time and sometimes I have my days when i still chug like a dragon).

3. Planning and preparation + organization. This has helped me too…It sets the stage for the dives. Calm, less anxiety, not rushing around. Planning and execution of dive calmly without darting around too much.

 

[Jim Lapenta]

I only got one notification of a reply so I missed most of this, but to respond to the reply about my dive shop, I have some answers. 1. They are not letting me guide their boat dives, just a shore dive to a reef at 20 ft depth that’s a 150 yard swim from shore, a place many do their open water cert dives, and it stays 20 feet for about 7 miles out so no risk of rogues exploring too deep. On boat dives I will only act as an assistant DM to learn and grow my experience. 2. I took the rescue diver course (which is required of a divemaster) that showed me, and I demonstrated, the proper actions to take in an emergency, including the one you mentioned. 3. There are 3 major organizations that certify DMs, PADI, NAUI, and SSI, two require 60 dives to complete DM and NAUI requires 70. So wherever you go, you may have a newer DM. 4. What kind of dives did you do? 20 of my dives were solo, the boat dropped us off and it was my responsibility to navigate from and to the boat on my own, as well as handle any problems (including myself getting tangled and handling it). I dove on a boat with a woman that had 200 dives, but neglected to inflate her bcd enough on entering and panicked so the DM had to assist her, so just because you have 200 dives with your husband holding hands at 30 ft in the Caribbean doesn’t mean you’re more experienced. 5. Usually the divemaster has more experience than you in diving that site, that alone gives them more “dives” in that spot, so listen to them. 6. How many DMs do you think have actually responded to a serious emergency? Most will be their first time too.
I completely understand your concern as a newer diver, as I had the same when I started, I did a boat dive with a DM that told me it was his first DM dive and was visibly shaking, but when scuba diving, the first rule is YOU are responsible for your safety, so get used to that. The DM designation is not a guarantee of perfection. It means they studied, and demonstrated the skills necessary. You are welcome to ask every DM you go with to give you their dive number, but if that’s all you go by, be ready to get anxious.
And as a response to my other posters, my rate has already increased with your suggestions. So thank you.

There are more than 3 agencies that certify DMs. And two of the ones you mentioned are pretty well known for churn and burn DM/Instructor courses. I've seen both that I would not feel comfortable in the pool with because they are so dangerous.
Standards to be a DM are pretty low. While I agree it's not the number of dives, more than a few of these DMs got that dive count by doing a series of 20-minute dives to 15 feet. I know my OW instructor had one guy where the running joke was if he fell in a puddle he'd log it as a dive.
IMO a DM should be able to handle any emergency that pops up on a dive. I also recommended to every student considering it to get a tech course or two under their belt first to help forget all the industry recreational diving BS they were fed about diving being safe, easy, and low risk.
The DM should also know when to leave people alone and not mess with their gear.
They should also know how to fix most gear problems they might encounter with the people they are guiding. Including saying the fix is your gear is broke and I don't care what you paid, you're not diving with me.
It should not matter if it's the first time they are responding to an emergency. They better do it right and in a calm professional manner. That means drilling over and over in rescue classes and planning a response on every dive.
They should also have experience in various environments and conditions.

 

[bdatud4x4]

like everyone has said SLOW DOWN, I am 5'9" 230lbs and by using controlled breathing and slow movement under water. Most of my dives last around 1Hr at 80' using aluminum80's. I usually have between 700-1000psi when i surface, that all depends on what type of current I'm in.
Check out HP steel 100's, I just changed over so I can carry less weight but it will help in your air as those are starting at close to 3500psi. good luck and safe diving.

 

[scubadada]

like everyone has said SLOW DOWN, I am 5'9" 230lbs and by using controlled breathing and slow movement under water. Most of my dives last around 1Hr at 80' using aluminum80's. I usually have between 700-1000psi when i surface, that all depends on what type of current I'm in.
Check out HP steel 100's, I just changed over so I can carry less weight but it will help in your air as those are starting at close to 3500psi. good luck and safe diving.

I assume you do not mean an average depth of 80 feet for an hour. Using an AL80, ending with 500 psi would take an RMV of 0.32 cu ft/min, 700 psi 0.29 cu ft/min, and 1000 psi 0.25 cu ft/min. Those would be extremely low average RMVs Average Gas Consumption Do you happen to know your avg RMV?

A HP steel 100 has a little over 30% more gas than an AL80, a bit more than 101 cu ft vs. a bit under 78 cu ft.

 

[Sudhakar123]

I started diving less than a year ago, but I immediately fell in love with it and went all in. I’ve started my divemaster course and intend to do the IDC after 6 months as a divemaster. I’m confident and comfortable with my skills, except air consumption. I’m 6’2” 240 lbs so I suck a lot of air. 20-30 ft I average an hour but at 50 ft it’s more like 35-40 mins (with 3 min SS and coming up with 5-6 bar). Will I encounter problems as a DM? Ive never been the diver that required the group to turn around because of low air, but worried I’ll lead a dive and have to turn before a paying customer needs to. Is there anything I can do to decrease my air consumption?

Over a period of time and dives you air consumption will go down….as u get more relaxed under water….

 

[bdatud4x4]

I assume you do not mean an average depth of 80 feet for an hour. Using an AL80, ending with 500 psi would take an RMV of 0.32 cu ft/min, 700 psi 0.29 cu ft/min, and 1000 psi 0.25 cu ft/min. Those would be extremely low average RMVs Average Gas Consumption Do you happen to know your avg RMV?

A HP steel 100 has a little over 30% more gas than an AL80, a bit more than 101 cu ft vs. a bit under 78 cu ft.

That's a max dive depth of 80' with average at around 60' and slowly take time to look at stuff and coming up for a 3min 15'deco stop.